Connecting electrode
FIELD OF THE INVENTION 
     The present invention relates to a connecting electrode for electrically connecting an internal battery of such as a semiconductor device card. 
     BACKGROUND OF THE INVENTION 
     FIGS. 3(A)-3(C) are views showing a conventional connecting electrode used in a semiconductor device card, in which FIG. 3(A) is a plan view and FIGS. 3(B) and 3(C) are sectional views taken along lines III(B)--III(B) and III(C)--III(C) of FIG. 3(A), respectively. In FIGS. 3(A)-3(C) reference numeral (1) designates a planar electrode substrate and reference numeral (2) designates a contact provided on the electrode substrate (1) and formed of a spring material, which has a convex surface (3) bent like a buttonhook and projecting from the electode substrate (1). The electrode substrate (1) and the contact (2) comprise the connecting electrode. 
     FIGS. 4(A)-4(C) are views in which the connecting electrode shown in FIG. 3 is mounted on a semiconductor device card with a battery in place. FIG. 4(A) is a plan view thereof and FIGS. 4(B) and 4(C) are sectional views taken along lines IV(B)--IV(B) and IV(C) --IV(C) in FIG. 4(A), respectively. Reference numeral (4) designates a frame of the semiconductor device card on which the electrode substrate (1) is mounted. Reference numeral (5) designates a battery pressed toward the right in FIG. 4(C), that is, toward the convex surface (3) of the contact (2) by means not shown. 
     Next, operation thereof will be described hereinafter. When one electrode of the battery (5) (not shown) is pressed against the contact (2) bent like a buttonhook as shown in FIGS. 3(B) and 3(C), the contact (2) receiving the force extends its bending part (6) and finally deforms into a straight line, that is, it is completely compressed as shown in FIGS. 4(B) and 4(C). Electrical connection between the battery (5) and the contact (2) is maintained by the elastic force by which the contact (2) tries to return to the original shape of a buttonhook. The other electrode of the battery (5) (not shown) is appropriately connected and then electric power is supplied to an electric circuit (not shown) of the semiconductor device card. 
     Since the conventional connecting electrode is constructed as described above, the force generated when the battery is in place completely compresses the contact. At this time, excessive stress is generated thereon and contact pressure between the battery and the contact generated by the elasticity of the contact is reduced due to fatigue or creep caused by vibration. As a result, the battery is not in contact with the contact when it receives external vibrations and then power supply is not applied to the electric circuit, causing stored information to be erased. 
     SUMMARY OF THE INVENTION 
     The present invention was made to solve this problem and it is an object of the present invention to provide a connecting electrode in which contact pressure between a contact and a battery is maintained for a long time. 
     These objects and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings. 
     A connecting electrode in accordance with the present invention comprises a projection on a surface of an electrode substrate on the same side as and beside a convex surface of a contact so that the amount of deformation of the contact is controlled when the contact is pressed against by a battery. 
     According to the connecting electrode of the present invention, a battery abuts the projection on the electrode substrate after it presses against the contact and the contact deforms to some degree. Thus, force from the battery is received by the projection. As a result, the contact does not deform excessively that it is prevented from being completely compressed. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1(A) is a plan view showing a connecting electrode in accordance with an embodiment of the present invention; 
     FIGS. 1(B) and 1(C) are sectional views taken along lines I(B)--I(B) and I(C)--I(C) in FIG. 1(A), respectively; 
     FIG. 2(A) is a plan view in which the connecting electrode shown in FIG. 1 is mounted on a semiconductor device card and a battery is in place; 
     FIGS. 2(B) and 2(C) are sectional views taken along lines II(B)--II(B) and II(C)--II(C) in FIG. 2(A), respectively; 
     FIG. 3(A) is a plan view showing a conventional connecting electrode; 
     FIGS. 3(B) and 3(C) are sectional views taken along lines III(B)--III(B) and III(C)--III(C) in FIG. 3(A), respectively; 
     FIG. 4(A) is a plan view in which the connecting electrode shown in FIG. 3 is mounted on a semiconductor card and a battery is in place; and 
     FIGS. 4(B) and 4(C) are sectional views taken along lines IV(B)--IV(B) and IV(C)--IV(C) in FIG. 4(A), respectively. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     An embodiment of the present invention will be described in detail with reference to the drawings. 
     FIGS. 1(A)-1(C) are views showing a connecting electrode in accordance with an embodiment of the present invention, in which FIG. 1 (A) is a plan view and FIGS. 1(B) and 1(C) are sectional views taken along lines I(B)--I(B) and I(C)--I(C) in FIG. 1(A), respectively. In FIG. 1, since reference numerals (1) to (3), and (6) designate the same parts as in a conventional example in FIGS. 3(A)-3(C) description thereof is omitted. Reference numeral (7) designates a projection provided on an electrode substrate (1) on the same side as and beside the convex surface (3) of the contact (2). In addition, projections (7) are provided on both sides of the contact (2) and on the same side of the substrate (1). 
     FIGS. 2(A)-2(C) are views in which the connecting electrode shown in FIG. 1 is mounted on a semiconductor device card and a battery is in place. FIG. 2(A) is a plan view and FIGS. 2(B) and 2(C) are sectional views taken along lines II(B)--II(B) and II(C)--II(C) in FIG. 2(A), respectively. Operation will be described with reference to these figures hereinafter. The electrode substrate (1) is mounted on the frame (4) on a semiconductor device. The battery (5) abuts the contact (2) and is pressed toward the right in the figure. Then, a bending part (6) of the contact (2) is bent by that force and the contact (2) deforms. However, since the battery (5) abuts the projection (7) after the contact (2) deforms to some degree, the force from the battery (5) is received by this projection (7). Therefore, the contact (2) does not deform excessively. More specifically, since an amount of deformation of the contact (2) is controlled by the projection, it does not deform in a straight line, that is, it is not completely compressed. As a result, stress of the contact (2) is reduced and a reduction in the elastic force of the contact (2) due to fatigue or creep is prevented. 
     Although there are two contacts (2) and a projection (7) is provided at each side of each contact (2) in the above embodiment, the number of these projections may be increased or decreased depending on the size of the battery or the structure of the electrode substrate. 
     As described above, according to the present invention, the projection is provided on the electrode substrate on the same side as the convex surface of the contact. Therefore, the force from the battery is received by this projection and the amount of deformation of the contact is controlled, so that its stress is reduced. As a result, contact pressure between the contact and the battery is maintained for a long time without any reduction of its elastic force. 
     Although the present invention has been described and illustrated in detail, it is clearly understood that the same is by way of illustration and example only and is not to be taken by way of limitation, the spirit and scope of the present invention being limited only by the terms of the appended claims.